Note: Descriptions are shown in the official language in which they were submitted.
CA 02823240 2013-06-27
Heavy cutting nozzle for cutting workpieces made of steel in particular
Description
The invention refers to a heavy cutting nozzle for cutting workpieces made of
steel
and workpieces made of iron alloys, particularly slabs, ingots and billets,
comprising a nozzle body with a thread for fastening to a cutting torch, a
centrally
arranged cutting oxygen channel, a multiplicity of heating gas channels
arranged
concentrically thereto on a specific inner pitch circle, and a multiplicity of
heating
oxygen channels arranged concentrically thereto on a further middle pitch
circle,
wherein the outflow openings of the media channels open out into a clearance
enclosed by the nozzle body.
Oxygen gas cutting torches are designed for cutting workpieces made of steel
and
workpieces made of iron alloys. These devices are used to efficiently cut
slabs,
ingots, and billets, for example. In this, the flame of the cutting gas torch
ignited
from a stream of oxygen and cutting gas is directed to the surface of the
metal to
be cut. Thereby, the metal is heated to its ignition temperature, whereby a
stream
of cutting oxygen oxidises the heated metal in order to provide for the
cutting
operation. In this, the workpiece starts burning and forms a joint extending
to
become a cut as the stream proceeds. Since heat is generated during the
process
described above, this flame cutting process is referred to as autogenous, i.e.
the
next steel layers of the spot to be cut are further pre-heated from the
temperature
gained from the burning steel.
As a matter of principle, a differentiation between premixed or postmixed
nozzles
and/or torches must be made. In premixed nozzles, heating oxygen and heating
gas are mixed within the torch head before streaming out for ignition. In a
postmixed cutting torch, the heating oxygen and the heating gas escape from
the
torch in an unmixed stream. Due to turbulences, the streams are mixed before
ignition.
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So-called postmixed cutting nozzles for a cutting torch device are known from
US
6,277,323 B1 and the CA 2,109,772 C, within the framework of which the media
heating oxygen, heating gas, and cutting oxygen are only mixed in the outflow
area of the flame. The nozzle is held by a retaining nut surrounding the
nozzle and
connected to the cutting torch. The nozzle is characterised by an axial
drilling for
the outflow of the cutting oxygen of a cutting torch. Furthermore, it contains
a
multiplicity of heating gas drillings arranged in an inner concentric circle
around the
axial cutting oxygen drilling. Moreover, the nozzle comprises a multiplicity
of
heating oxygen drillings arranged in an outer concentric circle around the
axial
cutting oxygen drilling. Each of the drillings, i.e. the axial cutting oxygen
drilling,
the heating gas drillings, and the heating oxygen drillings open out to
outflow
openings at an outlet end migrate in a cylindrical clearance within the
retaining nut
where the cutting flame is generated.
Therefore, this nozzle is an externally mixing ¨ also called "postmixing" ¨
nozzle,
i.e. there is no mixture of the media inside, but outside of the nozzle.
Furthermore,
the nozzle is designed in several parts due to the additional retaining nut so
that
the nozzle design is expensive and complex. Moreover, a relatively large
cutting
joint is generated. Additionally, contaminations such as cinder, dust, and
dirt
particles may accumulate on the outflow area of the flame in the cylindrical
clearance within the retaining nut, where these can also penetrate the nozzle
shortening the service life of the cutting nozzle.
The task of the invention is to create a heavy cutting nozzle of the type
mentioned
above, during the operation of which the formation of steel / cinder particles
is
lower, that creates a smaller and smoother cutting joint at lower noise
levels, and
that allows for an extended service life of the nozzle.
In accordance with the invention, the problem is solved by the clearance
enclosed
by the nozzle body being designed from the outflow openings of the media
channels for cutting oxygen, heating oxygen, and heating gas towards its
outflow
end in an angular, conical or approximately semicircular shape and, in this
way,
having the effect that the media flowing out are diverted at the inclined or
curved
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outlet surfaces towards the centre of the nozzle, and swirl with the
surrounding air
at a distance farther away from the heavy cutting nozzle outside the nozzle
body.
When compared to the traditional cutting nozzles, the workpiece to be cut can
be
preheated and cut in a larger distance between heavy cutting nozzle and
workpiece surface due to the arrangement of the media channels in the nozzle
body of the heavy cutting nozzle, the special geometric design of the media
channels for the supply of gas and oxygen, as well as the heating and flame
cutting temperature required for autogenous flame cutting. Furthermore,
cutting
with this heavy cutting nozzle produces less steel/cinder particles on the
workpiece surface and at the heavy cutting nozzle. The cutting joint is
smaller and
smoother and the generated noise is lower. Moreover, the service life of the
heavy
cutting nozzle can be extended significantly.
With this nozzle design, the process of mixing heating gas and heating oxygen
and the related highest achievable combustion temperature, as well as the
protection of the escaping stream through the outer protective jacket
consisting of
the air/oxygen mixture is performed at a higher distance between heavy cutting
nozzle and workpiece surface.
The sub-claims result in further embodiment features and advantages.
According to that, the outflow surfaces of the media channels are located
inside
the nozzle body and can be combined with each other, if required. The angular,
conical, or semicircular or possibly even cylindrical clearance for the
outflow of the
media, namely cutting oxygen, heating oxygen, and heating gas, resulting
thereof
guides the escaping media.
In the supersonic flow range, the escaping gases are directed towards the
middle
in the area of the inclined and/or curved outflow surfaces and have the effect
that
the media swirl significantly farther away from the heavy cutting nozzle.
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In accordance with a further development of the heavy cutting nozzle according
to
the invention, a multiplicity of oxygen channels runs through the nozzle body
and
opens out into a ring-shaped groove at the outflow end of the nozzle body so
that
additionally escaping oxygen forms a pipe-shaped protective oxygen wall and/or
a
protective jacket. This jacket protects the outflow surface against
contamination by
dirt particles created during flame cutting. These particles are blown off the
protective jacket of the escaped oxygen by the outflow surface of the nozzle.
This
way, the protective jacket prevents the dirt particles from gluing to the
nozzle outlet
end due to the cooling effect of the oxygen. Moreover, the air/oxygen mixture
additionally escaping from the ring-shaped groove forms the protective oxygen
jacket around the cutting oxygen, the heating gas, and the heating oxygen
preventing premature swirling in the margin areas and minimising the generated
noise levels.
Furthermore, it is designed that the ring-shaped groove is characterised by a
variable cross-section, preferably semicircular or rectangular.
Moreover, the oxygen channels can be equipped with at least one further, rear-
mounted channel for sucking ambient air, whereby the channel runs from the
outside of the nozzle body to the respective oxygen channel.
Furthermore, the clearance enclosed by the nozzle body has a cylindrical shape
from the outflow openings of the media channels towards its outflow end and
the
media channels open out into the outflow surface of the clearance enclosed by
the
nozzle body in a rectangular shape.
The underlying idea of the invention is described in more detail within the
framework of the following description on the basis of an exemplary embodiment
shown in the drawings. The figures show the following:
Fig. 1 shows a heavy cutting nozzle according to the invention in
accordance
with view "Z" pursuant to Fig. 2 on the outflow openings of the media
channels,
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Fig. 2 shows a longitudinal section view of a heavy cutting nozzle along
line A ¨
A according to Fig. 1,
5 Fig. 3 shows a sectional view of the heavy cutting nozzle along
line B ¨ B
according to Fig. 1,
Fig. 4 shows a view "Y" of the heavy cutting nozzle according to Fig. 5,
Fig. 5 shows a sectional view of the heavy cutting nozzle along line C ¨ C
according to Fig. 4,
Fig. 6 shows a sectional view of the heavy cutting nozzle along line D ¨
D
according to Fig. 4,
Fig. 7 shows detail "X" according to Fig. 6 in a second embodiment, and
Fig. 8 shows detail "X" according to Fig. 6 in a third embodiment.
The heavy cutting nozzle 1 according to Fig. 1 to Fig. 8 for cutting a
workpiece 200
is equipped with a nozzle body 2 designed as one piece. The nozzle body 2 is
equipped with a hexagonal bolt 3 along the circumference. Another section of
the
outer circumference of nozzle body 2 is characterised by an outer thread 4 in
order
to screw this to a cutting torch 100 represented schematically in Fig. 3 using
a
suitable tool.
Fig. 1 shows the distribution of the outflow channels for the media required
for the
cutting procedure. In the centre of the nozzle body 2 there is an axial
cutting
oxygen channel 5 covering an area from the inlet side 6 up to clearance 7 on
the
outflow area 8 of the nozzle body, as can be seen in Fig. 2. Regarding this
embodiment of the heavy cutting nozzle 1, clearance 7 has a pan-shaped
cylindrical design.
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In its end area directed towards the clearance 7, the axial drilling 5
comprises a
conical extension, by means of which the cutting oxygen flowing through the
cutting oxygen channel 5 is accelerated regarding its speed and, thus, its
energy.
At this end of the axial drilling 5 the cutting flame is formed.
Parallel to the cutting oxygen channel 5, a multiplicity of heating gas
channels 10
is designed in an inner pitch circle 10.1 that are arranged concentrically
within the
nozzle body 2.
Furthermore, within a middle pitch circle 11.1, the nozzle body 2 comprises a
multiplicity of heating oxygen channels 11 running parallel to the cutting
oxygen
channel 5 from the inlet end 6 of the heavy cutting nozzle 1 to the clearance
7 of
the nozzle body 2.
Moreover, at its outflow end, the nozzle body 2 comprises a ring-shaped groove
12 surrounding the clearance 9 for further oxygen channels 13 running from the
middle pitch circle 11.1 from the inlet side 6 inclined towards the groove 12.
The longitudinal section A ¨ A through the nozzle body 2 shown in Fig 2 in
accordance with Fig. 1 shows the course of the cutting oxygen channel 5, the
heating gas channels 10, and the heating oxygen channels 11. The media
channels 5, 10, and 11 open out into clearance 7.
Fig. 3 shows a longitudinal section B ¨ B through the nozzle body 2 in
accordance
with Fig. 1 containing a cutting oxygen channel 5, a heating oxygen channel
11,
and an additional oxygen channel 13 towards the ring-shaped groove 12.
Furthermore, another channel 14 for sucking the ambient air 15 is designed in
each case, opening out in the assigned oxygen channel 13 and running from the
outer side of the nozzle body 2 to this channel in an inclined manner. The
media
channels 5 and 11 escape in clearance 7 at the outflow surface 8. The
additional
oxygen from the further oxygen channels 13 escapes together with the ambient
air
15, caught by the suction effect, of the channels 14 in the ring-shaped groove
12
and forms a pipe-shaped protective oxygen wall 16 around the cutting flame in
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order to improve the flame's efficiency. The process of mixing heating gas and
heating oxygen and the related highest achievable combustion temperature "T",
as
well as the protection of the escaping stream through the protective jacket
consisting of an air/oxygen mixture is performed at a higher distance "A"
between
Fig. 4 again shows the view in accordance with Fig. 1 in order to illustrate
the
sections C ¨ C and D ¨ D in Fig. 5 and Fig. 6.
Fig. 5 shows a longitudinal section C ¨ C through the nozzle body 2 with the
cutting oxygen channel 5, the heating gas channels 10, and the heating oxygen
channels opening out into the clearance 7. With the embodiment 11, the
clearance
7 enclosed by the nozzle body 2 is designed conically so that the heating gas
and
heating oxygen media pass through the clearance 7 in an inclined manner and
mix, causing the media to swirl at a distance "B" farther away from the heavy
cutting nozzle 1.
Fig. 6 shows a longitudinal section D ¨ D through the nozzle body 2 in
accordance
with Fig. 4 running through the heating oxygen channels 11, the cutting oxygen
channel 5, and the additional oxygen channel together with channel 14 for
sucking
ambient air 15 towards the ring-shaped groove 12. The media channels 5 and 11
open out into the conical clearance 7. The additional oxygen of the channels
13
and 14 escapes into the ring-shaped groove 12.
Fig 7 shows an embodiment modified on the basis of Fig. 6, within the
framework
of which the clearance 7 is characterised by a predominantly tapered and/or
conical shape, whereby the tapered and/or conical surface is characterised by
angular surfaces.
Fig. 8 shows a detail X in accordance with Fig. 7, whereby the media outflow
for
cutting oxygen and heating oxygen opens into an approximately semicircular
clearance 7.
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Of course, the features mentioned above can not only be used in the
combination
specified in each case, but also in other combinations or alone, without
leaving the
framework of the present invention.
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List of reference numbers
1 Heavy cutting nozzle
2 Nozzle body
3 Hexagonal bolt
4 Outside thread
Cutting oxygen channel
6 Inlet side
7 Clearance
8 Outflow area
9 Conical extension
Heating gas channel
10.1 Inner pitch circle
11 Heating oxygen channels
11.1 Middle pitch circle
12 Groove
13 Oxygen channels
14 Channel
Ambient air
16 Protective oxygen wall
100 Cutting torch
200 Workpiece
A Distance
B Distance
T Combustion temperature
